In recent years, attention has been paid to a semiconductor storage apparatus (a silicon disk) using, as a storage medium, a nonvolatile memory that is typical of an NAND type flash memory as a substitution for a hard disk apparatus. The reason is as follows. In contrast from a hard disk apparatus, a semiconductor storage apparatus does not provide an element causing a failure such as a rotating mechanism, reduces consumed power, provides continuous use for 24 hours, does not make an operation sound, and provides a shock resistance to vibration. In the semiconductor storage apparatus of this type, however, the number of times for rewriting data is limited to approximately several ten thousands to several hundred thousands times as an typical apparatus lifetime. In addition, if the rewrite concentrates in a specific area (a storage element), the lifetime is further shortened. The technique for eliminating the problems that have been described in Patent Document 1 is well-known.    Patent Document 1: Japanese Patent Publication 05-204561 A
The Patent Document 1 has described a semiconductor storage apparatus (a semiconductor disk) including, in a flash memory, a data memory area for storing data, a substituting memory area for substituting an error region in the data memory area, and an error memory area having, as error information, an address of a substituting memory of a data memory in which an error is generated, and having a memory controller for carrying out read/write from/to each of the areas. With the structure, the memory controller reads the error information in the error memory area and carries out the read/write from/to the data memory area when the data memory area is normal and the substituting memory area when the data memory area is abnormal. In the writing operation, if the error is generated, an empty region in a defective block substituting area is searched and data are written to the empty region, and error information about the memory area having an error is updated. The control is carried out to save the error caused by the rewrite of the flash memory, thereby prolonging a lifetime of the semiconductor storage apparatus.